Today we talked about barriers to proving and other complexity-theory results: specifically, the "relativization" barrier introduced by Baker-Gill-Solovay, and the "natural proofs" barrier introduced by Razborov-Rudich.
We also talked about results that evade them. For example, the Hopcroft-Paul-Valiant Theorem, , and the Paul-Pippenger-Szemeredi-Trotter Theorem, , do not relativize. Nor do they algebrize, according to the Aaronson-Wigderson notion. (At least, my opinion is that the notion of relativizing/algebrizing makes sense for these theorems, and in this sense they do not relativ/algebrize.)
As for natural proofs, we discussed how proofs by diagonalization do not seem to naturalize, and we mentioned explicit circuit lower bound which are by diagonalization; for example, Kannan's result that not in .
Finally, we mentioned some theorems that neither relativize nor (seem to) naturalize: for example, Vinodchandran's Theorem that not in , and Santhanam's improvement of this to an explicit promise problem in which isn't in .
Thursday, April 30, 2009
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Are there any notes that could be posted? (I had to leave for a thesis defense.)
ReplyDeleteMy notes for this aren't so polished; I'll email them to you.
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